Polycarbonates are well known thermoplastic materials which, due to their many advantageous properties, find use as thermoplastic engineering materials in many commercial and industrial applications. The polycarbonates exhibit, for example, excellent properties of transparency combined with toughess, flexibility, impact resistance and high heat distortion temperatures. The polycarbonates and their preparation are disclosed, for example, in U.S. Pat. Nos. 3,028,365; 3,334,154; 3,275,601 and 3,915,926. However, due to their relatively high melt viscosities the carbonate polymers need relatively high processing temperatures. It would thus be very advantageous if polycarbonates could be provided which while retaining substantially all of their other advantageous properties were also easier to process, i.e., exhibited lower melt viscosities.
It is, therefore, an object of this invention to provide carbonate polymers which exhibit improved processability and at the same time retain substantially all or most of the other advantageous properties of polycarbonates.